The present invention relates to a hinge for interconnecting the back part and seat part of an automotive-vehicle seat.
More particularly this invention concerns such a hinge which permits the back part to pivot forwardly on the seat part yet which allows the back part to be fixed relative to the seat part.
In a two-door motor vehicle it is normally necessary to pivot forward the back part of each front seat in order to enter or have access to the back part thereof. To this end hinges are provided between the seat part and back part. In order to adjust the front seats these hinges are normally provided with a mechanism that allows the rest position of the back part of the motor-vehicle seat to be adjusted. Furthermore, federal regulations now require that the back part be non-pivotal relative to the seat part under normal conditions so that in the event of a frontal collision the seat backs will not pivot forwardly, projecting the front-seat passengers forwardly also.
Thus such a hinge normally comprises an upper hinge element secured to the back part of the motor-vehicle seat and a lower hinge element fixed to the seat part. A pivot is provided between these parts. One of the parts also normally carries a pivotal positioning plate that can be pivoted about the pivot between the two parts and which can be positioned in any of a plurality of angularly offset positions and fixed in this position relative to one of the hinge elements. This positioning plate constitutes an abutment engageable with the other of the hinge elements and serving to define the rest position of the back part relative to the seat part. A toothed portion of the positioning plate to this end is normally engageable with a toothed pawl that can be displaced radially into and out of mesh with the teeth of the positioning plate and fix it in any of the angularly offset positions.
Furthermore the positioning plate normally has a stop formation which is directed toward and engageable with a pivotal pawl provided on the other hinge element. This pawl has an end face flatly engageable with the stop formation so as normally to prevent forward pivoting of the back part relative to the seat part. An operating button or lever is provided on the back part which when actuated pulls the end face out of alignment with the stop formation and allows the back part to pivot forwardly.
Thus in order to enter or gain access to the rear side of the motor vehicle, it is necessary to simultaneously actuate the release button and displace the back part forwardly. Usually this operation requires two hands. Not only is such an operation cumbersome, but the extra mechanism for operation of the release lever or element considerably increases the cost of the hinge assemblies for the motor-vehicle seats.